For many years specially constructed traction vehicles have been available which operate both on roads and on railroad tracks. Typically they are small rail locomotives with four road wheels which can be raised to permit ordinary railroad travel on rail wheels or lowered to the ground so as to lift the rail wheels and permit road travel. Examples are the vehicles described in U.S. Pat. Nos. 3,198,137, 3,884,156, 4,067,259, 4,167,142 and 5,168,815. They are of relatively complicated design and quite expensive.
The object of the present invention is to achieve all of the major functions of these known specially built road-rail vehicles at a small fraction of their cost. This is achieved by utilizing a conventional farm tractor for whatever road travel is required of the road-rail vehicle, whether to pull loads or simply to move on the ground from one rail site to another. Then for rail operation a special conversion module is to be attached beneath the farm tractor. This module is to have vertically movable rail wheels which can be retracted upwardly to allow the farm tractor to continue its ordinary functions travelling on the ground. When rail travel is required the rail wheels are to be lowered to tracks so as to lift the tractor and elevate its road wheels off the ground. The tractor engine through its conventional power take-off is to drive the rail wheels and move the vehicle along the railroad track either alone or pulling railroad cars.